There are many devices powered with electricity and operated by people. An example of this human-machine interaction is a motor drive attached to a load and operated by a user. Nowadays, the motor drive usually includes a frequency converter.
The frequency converter can receive control parameters through an external interface, which can be a front panel on the converter or an electrical/optical communications interface, for example. However, there is no natural, intuitive way for a user to interact directly with the motor drive.